The functional vessels of human and animal bodies, such as blood vessels and ducts, occasionally weaken or even rupture. For example, in the aortic artery, the vascular wall can weaken or tear, resulting in dangerous conditions such as aneurysms and dissections. Upon further exposure to hemodynamic forces, such an aneurysm can rupture.
One intervention for weakened, aneurismal, dissected or ruptured vessels is the use of an endoluminal device or prosthesis such as a stent graft to provide some or all of the functionality of the original, healthy vessel and/or preserve any remaining vascular integrity by replacing a length of the existing vessel wall that contains the site of vessel weakness or failure. Stent grafts can effectively exclude the aneurysm by sealing both proximally and distally to the aneurysm, and shunting blood through its length. A device of this type can, for example, treat various arterial aneurysms, including those in the thoracic aorta, abdominal aorta, iliac, or hypogastric artery.
Conventional stent grafts are generally formed from a tube of biocompatible material in combination with one or more stents permanently attached to the graft prior to insertion into the body to maintain a lumen therethrough. In some cases, the stents are individual rings placed along the length of the graft and either connected to one another by some means, such as struts, sutures and the like, or are affixed to the graft material by means such as suturing to, gluing to, weaving through, or encasing in the graft material. Other stents are single body stents such as laser cut tubes, mesh or braided tubes, helically coiled tubes, and the like.
In all of these instances, the stents are substantially permanently attached to the graft material and remain attached to the graft material after placement in the vessel. Hence, once the stent graft is placed in the vessel, the stents cannot be repositioned within the graft or removed from the graft, unless the entire device is surgically removed.
In addition, in many instances, the graft material that contacts the vessel wall over time becomes part of the vessel wall, such as in the case of aneurysm repair, and hence, replaces the native vessel. In this case, many of the stents in the stent graft may no longer be needed. And, over time, the stents may break and wear through the graft material, necessitating repair of the graft, and forcing the patient to endure yet another procedure.
Further, many current stent grafts are limited in their ability to accommodate a tortuous native vessel, the shape of which may change over time. Stent grafts may need to be more flexible in certain areas than in others. However, once placed, there is little or no ability to adjust the stent graft in situ to accommodate tortuosity or changes in vessel configuration.
Thus, there remains a need for a customizable stent graft that can accommodate individual anatomies and can be reconfigured in situ and/or removed from the body as needed.